1. Field of the Invention
This invention relates to techniques of delivering parts in an assembling plant.
2. Description of the Prior Art
In an assembling plant, parts transported from parts factories are received in a parts reception place, and the received parts are delivered to places where they are used. This status is illustrated in FIG. 1. As shown, parts W1, W2, . . . which are transported by trucks or the like from parts factories, are successively received in a parts reception place 11 and transferred to delivery wagons 12. The parts transferred onto the delivery wagons 12 are delivered to parts use positions L1 to Ln by parts deliverers 14, 15, . . . running along a course 13 extending along the parts use positions L1 to Ln. The delivered parts W1, W2, . . . are used at parts use position L1 to Ln, respectively, for assembling a product or products.
Normally, the parts deliverers 14, 15, . . . are scheduled to depart from the parts reception place 11 at predetermined time instants. The transportation of the parts W1, W2, . . . from parts factories, however, is not always scheduled by taking the time required for the delivering operation of the parts deliverers 14, 15, . . . into considerations. Therefore, if the parts deliverers 14, 15, . . . are managed under a rule that all parts existing at the parts reception place 11 at a timing when each parts deliverers 14, 15, . . . departs from the parts reception place 11, the time required for the delivering operation by the parts deliverers is not constant, but some deliverers may require long times for the delivering operation while other may require short times.
FIG. 1 shows a case in which the parts W1 to W4 have already been received in the parts reception place 11 at the time of the departure of the parts deliverer 14, while the parts W5 are delivered after the departure of the parts deliverer 14 and before the departure of the parts deliverer 15. In this case, if all the parts W1 to W4 are delivered by the parts deliverer 14, the delivering operation is excessive for the parts deliverer 14 while it is insufficient for the next parts deliverer 15. As shown in FIG. 1, the burden of the delivering operation may be averaged by changing the deliverer for the parts W4 from the deliverer 14 to the deliverer 15.
When excessive parts have been received in the parts reception place 11 as in the above case, it is in practice in the prior art that the personnel in charge of the parts delivery determines parts to be delivered by the parts deliverer 14 at this time and other parts which are to be left for the next parts deliverer 15. Shown in FIG. 1 is an exemplary case in which the parts W1 to W3 are delivered by the parts deliverer 14 while leaving the parts W4 for the next parts deliverer 15 to deliver the parts W4 together with newly delivered parts W5 by the next parts deliverer 15.
At this time, it is not so easy to determine which parts are to be delivered at this time and which parts are to be left for the next deliverer so that the delivering operation time for each parts deliverer are substantially uniformalized. A graph labeled (A) in FIG. 1 shows an example of delivering operation times T1 to T5 required for the individual parts W1 to W5. In this example, the total delivering operation time T14 required for the parts deliverer 14 to deliver the parts W1 to W3 is extremely long compared to the total delivering operation time T15 required for the parts deliverer 15. In this case, it may be thought to shift the parts W3 from the parts deliverer 14 to the parts deliverer 15. Doing so, however, leads to an excessive total delivering operation time for the parts deliverer 15.
Up to date, it has been in practice to leave the assignment of the parts W1, W2, . . . received in the parts reception place 11 to the parts deliverers to the experience and skill of the operators, and the time or burden for the delivering operation between adjacent parts deliverers is not uniformalized at all times.